Geology, geography and global energy

Scientific and Technical Journal

Geological structure of negative forms (muld) salt-crop structural floor of Astrakhan course

2018. №4, pp. 52-58

Ushivtceva L.F. - C.Sc. in Geology and Mineralogy, Associate Professor, Astrakhan State University, 1 Shaumyan sq., Astrakhan, 414000, Russian Federation,

Zakharchuk V. A. - C.Sc. in Geology and Mineralogy, Associate Professor, Astrakhan State University, 1 Shaumyan sq., Astrakhan, 414000, Russian Federation,

A characteristic feature of the geological structure of the territory of the Astrakhan arch is the presence of a powerful sedimentary cover up to 8-12 km, consisting of three rock complexes: subsalt, salt-bearing and supersalt, differing in lithological features and structure. The presence of a powerful halogen Kungur stratum and manifested salt tectogenesis led to the formation of a salt dome structural floor. The nature of the manifestation of salt tectogenesis, the degree of its intensity, the thickness of the salt-bearing and overlying strata, the multidirectionality of tectonic movements predetermined the diversity of structural forms: from gentle dome-shaped uplifts to salt bodies in the form of arrays, columns, ridges and ridges with a complex configuration, with different depths of the salt core, the degree of penetration of the overlying sediments, formation time and other features and their layers. The introduction of salt rods in the super-salt complex violates the conditions of its occurrence in a limited area near the domes, and in the inter-dome zones - troughs, the structure of the super-salt complex remains virtually unbroken. Most of the troughs, predominantly of the ancient foundations, are made of Upper Permian sediments of considerable thickness, and only a few troughs are composed of Paleogene sediments. Along with the processes of salt tectogenesis, post-sedimentary changes in the rocks are observed, as evidenced by the orientation and elongation of the grains of halite and anhydrite, thin banding; isometric or fluid form of grains, salt filling cracks, intense pyritization on the bedding planes, crushing of non-salt rocks, presence of debris, sliding mirrors. The features of the internal structure of the section, the mineralogical, petrographic composition, and physicomechanical properties of heterogeneous in composition rocks cause geological complications at the autopsy - the occurrences, the plastic flow of salts and inter-salt viscous clays, debris, collapses, grope formation, etc.

Key words: солянокупольные структуры, гряды, межкупольные пространства, мульды, соляной тектогенез, постседиментационные процессы, верхнепермские отложения, осложнения, рапопроявления, смятие колонн, salt-dome structures, ridges, inter-dome spaces, troughs, salt tec